1. Field of the Invention
The present invention generally relates to a wrist exerciser, and in particular to a separable casing structure of a wrist exerciser.
2. The Related Art
Wrist exercisers comprising a hollow casing inside which a spherical rotor is rotatably supported are known for exercising wrist-related muscles and rehabilitation purposes. Examples are shown in Taiwan Utility Model No. 135058 and U.S. Pat. No. 5,800,311. FIGS. 21 and 22 of the attached drawings show a conventional wrist exerciser, generally designated with reference numeral A. The wrist exerciser A comprises a spherical, hollow casing comprised of an upper hemispherical casing member A1 and a lower hemispherical casing member A2. The upper and lower casing members A1, A2 mate each other to form the casing in which a spherical rotor A3 is rotatably mounted. By rotating the casing to causes rotation of the rotor A3, a centrifugal force induced by the rotor A3 is applied to a user's palm for exercising the wrist-related muscles.
The casing members A1, A2 are fixedly attached to each other by means of for example ultrasonic welding whereby separation the casing members A1, A2 without damage to the casing itself is in general impossible. Under this circumstances, it is not possible for a general user to change any parts of the wrist exercise, including the casing members and the rotor, or doing any repairing of the rotor.
Furthermore, to be more attractive to the general users, some of the wrist exercisers include sound and light generators mounted in the rotor A3 whereby when the rotor rotates, colorful patterns of lights and sounds are generated. Some of the wrist exercisers include a counter for counting the turns of the rotor A3. All these devices are fixed inside the casing. There is in general no way for users to replace or change these devices.
Thus, it is desired to have a wrist exerciser having a separable casing for overcoming the above problems.